More than 300 new jobs are being created by Craigavon-based Almac as part of a £54 million expansion.
The pharmaceutical firm is expanding its business over the next five years.
Almac provides services to more than 600 companies - including world leaders in the pharmaceutical and biotech sectors.
It's yet another boost for Northern Ireland's burgeoning pharmaceutical sector.
The 348 new positions will be created across two areas of the business.
Some 141 staff will be added to Almac Pharma Services to meet the growing demand for "outsourced development services".
A further 181 will be created in 'clinical services'.
That arm of the business deals with clinical packaging, labelling and logistics.
The firm has also added 26 "high value core support positions" within areas such as IT and engineering.
Chief executive Alan Armstrong said the company was "fortunate to employ an excellent highly-skilled workforce".
"It's fantastic that demand for our services has resulted in the creation of so many new jobs as we embark on further expansion over the next five years," he said.
It's only a year since the first added a further 229 staff to its workforce in a £13.7 million expansion.
In addition to Craigavon, the group has also invested large sums in a North American headquarters in Pennsylvania.
Invest NI is putting forward £5.5 million towards the latest expansion.
Enterprise minister Arlene Foster said the "significant investment" would enable the company to "expand the range of services it can offer".